The Moles Are Back!––

Taking The Battle Of The Backyard Underground

By Ed Hutchison

Associated Press

Of moles, one thing is certain: They are back.

Actually they never left for the winter; it only seems like they did.

Several types of moles inhabit the United States, but two really drive gardeners crazy in many areas of the United States with their burrowing and tunneling across lawns, around building perimeters, and through flower beds: the eastern mole and star-nosed mole. Each is about the size of a chipmunk and weighs just three to six ounces.

But oh, what trouble is packed into those tiny packages of hunger and digging talent.

Contrary to popular belief, moles do not leave their home area over winter. Instead, they burrow even deeper in the soil and either hibernate or remain mildly active, feeding on soil insects that likewise dig deeper for winter.

It seems far less certain what works at eradicating them, at least judging by the methods people use. Popular choices include chewing gum, human hair, moth balls, broken glass, bleach, red peppers, razors, smoke bombs, water, exhaust fumes, rodent poison, vibrating probes, and more.

The theory is simple: Either flush out or entomb the moles in their tunnels with smoke bombs, carbon monoxide, or water, poison them, asphyxiate them, or drive them away with repugnant odors.

What makes the mole-away task so frustrating is that seldom are one of the critters seen above ground. Instead, they spend their time underground looking for and feasting on earthworms, millipedes, pill bugs, and assorted other insects found around home foundations and especially, in the rich, loose soil of landscape beds and flower gardens.

Scientists have determined moles eat 25 to 100 percent of their body weight each day, which means a lot of insects and a lot of tunneling, much to the homeowner’s chagrin.

Moles also eat grubs, those dirty-white C-shaped larvae of various beetles. Grubs eat the roots of grass, and an overzealous population can damage large areas of the lawn. And that can lead to disaster; the grubs killing off the grass, getting fatter by the day, while the moles chase after them, underground. Lawns can look shabby in no time.

One control measure is ridding the lawn of grubs. Insecticides labeled for this are available and generally effective, if applied at the right time. Another approach is to apply what is called milky spore to the lawn, a biological control that relies on the bacteria Bacillus popilliae. It essentially causes the grubs to quietly blow up soon after they have ingested it. Generally, milky spore takes a few years to build a sufficient population in the soil for effective grub control. It then remains active for several years. It is similar to other biological controls for cabbageworm, mosquitoes, and other insects.

Still, it is important to keep in mind that moles favor earthworms and these are usually found in soil that is rich and loamy, as opposed to hardpacked clay or sand. They burrow more easily in soil that is loamy and their search for food is easier because there are more insects, especially earthworms. Moles find the going especially easy in mulched beds because the top several inches are loose, a good environment for earthworms and digging. They also like to tunnel along foundation lines.

Damage to beds is usually minimal: a bit of earth upturned and perhaps some plants uprooted.

But to lawns, it can be more severe. Burrowing near the surface separates grass roots from soil, and that leads to yellowing along the tunnel. Stepping on a tunnel yields a soft feeling underfoot. At best, the ridges left behind –– or the mounds of soil –– are unsightly. Last year’s runs can become unsightly in the spring because of heaving of the soil from freeze-thaw cycles.

Moles are well equipped to work in soil. Scientists report that a mole essentially plunges into the earth, thrusts its forefeet into the soil, and then follows with head and body as it rotates its forelimbs and pulls the loosened dirt behind it. A busy eastern mole can burrow forward about 18 feet per hour.

So, if gas, smoke bombs, razor blades, chewing gum, and other concoctions do not work, how do you rid your property of moles?

Experts do not totally agree on this. Some believe that an application of castor oil sprayed on the lawn contaminates the moles’ food source and drives the critters off. Most agree that stuff like chewing gum, smoke bombs, and other tricks are not effective, especially long term. But most agree that the best way to get rid of moles is to trap them, which essentially means skewer them with a sharp metal rod as they are burrowing among their tunnels.

Several types of traps are available and all take some finesse in setting up.

From a timing perspective, probably the best time to trap moles is before they breed in early spring. Timing varies across the country; in the Midwest it occurs toward late March. Usually, four to six moles are born live, underground, and after three weeks of nursing, leave the nest.

The homeowner does have a few biological advantages. One is that the number of moles occupying a property is relatively small; some estimates are just four or five for each acre of so. The second advantage is that moles are essentially loners. They do not travel in packs and seldom will they use another mole’s active tunnels.

The mole has a few advantages, too. Its wily behavior is confusing: Which tunnels are active, which are not? How to set a trap? How do you know if the trap was effective? Why are moles invading my yard, from the neighbors'? And so on.